Synergistic stabilizing compositions



Unite States 1 2,917,377 Patented Dec. '15, 1 959 2,917,377 SYNERGISTIC sranrrizmo coMPosmoNs No Drawing. Application -May 9, 1956 Serial No. 583,638

15 Claims. (Cl. 44-72 Stabilization of hydrocarbons, andparticularly, motor fuels or the. like, is necessary apparently due to a number of reasons. One reason is concerned with the unsaturated constituents of the hydrocarbon fuels themselves. This. is stated, for example, in US. Patent No. 2,310,710, dated February 9, 1943, to Rosenwald et al. in the following language:

fThis invention relates to a method for stabilizing olefin-containing hydrocarbon oils, and more particularly, cracked gasolines of the petroleum origin. However, gasolines from other sources, such as coal tar, shale oil, etc., may be also treated according to the present invention, as may those made by polymerization of olefins, reforming of naphthas, etc.

More specifically, the invention concerns a method for stabilizing olefin-containing gasolines during storage in respect to their valuable properties such as color and anti-knock value and low gum content wlnch tend to depreciate because of the, action of oxygen upon the olefins in said gasolinesr i H The cracking and reforming processes which are employed to produce additional yields of gasoline from heavy hydrocarbo'naceous oils, or to increase. the antikno'ck properties of naphthas and straight-run gasolines, produce motor fuels having substantial concentrations of unsaturated hydrocarbons, particularly mono-olefins and di-olefins. These olefinic hydrocarbons tend to form peroxides and gums when stored in the presence of oxygen. The use of inhibitors to prevent, such reactions'has been practiced, and many types of compounds have been suggested for this purpose, including aminophenols, wood tarfractions, polyhydroxy phenols, etc.

In one specific embodiment, the present invention comprises the treatment of unstable olefin-containing gasolines to preserve their valuable properties in respect to gum content, color and anti-knock value by adding thereto minor quantities of 2-alkyl-4-alkoxyphenols of the general structure wherein R comprises any alkyl group and OR is an alkoxy group wherein R is of the same or difierent molecular weight and structure than R.

The properties desirable in a gasoline gum inhibitor are as follows:

(a) Solubility is the gasoline to a degree in excess of the maximum concentration in which it is likely to be used.

(b) High degree of potency so that relatively small concentrations can be used. I

(c) Insolubility or relatively low solubility in water or aqueous alkaline or acidic solutions with which the gasoline is likely to come on contact.

(d) Either normally liquid or having a high degree of solubility in a non-aqueous, gasoline-miscible solvent thus increasing theease of handling and addition to the gasoline. I p I s (e) Non-reactive with tanks, fittings, lines, engine parts, etc., with which the gasoline is likely to come in contact. I p g (f) Of light color, and imparting or developing no objectionable color orodor to the gasoline when added or during storage. 7

The inhibitors of the present invention to a large 'ex tent fulfill these requirements. K V ,7 a v The degree of insolubility of an inhibitor in water or caustic solutions is of particular importance since gasoline storage tanks generally contain water which is alkaline in reaction. If the inhibitor is soluble in the water layer, it is partially removed from the gasoline and thus itseftect is greatly reduced. The present type of compoundhas been found to be practically insoluble in water and in most cases to be but slightly removable from gasoline by contact with dilute alkaline solutions.

The compounds of the present invention are useful for preventing the deterioration of gasoline, but different individual compounds of the same type are not. necessarily exact equivalents. I u

With widespread use of tetraethyl lead it has been recognized that the mere presence of tetraethyl lead introduces a new factor, at least in part, whichmakes the stabilization of a leaded rnotor fuel more difficult. Irideed, tetraethyl lead seems to render straight-run gasolines, i.e., those free from constituents obtained by oracle ing processes, s'ufii'ciently susceptible to deterioration that protection is required which normally would not be necessary. A further possibility is that the tetraethyl lead may decompose, at least in part, and be the source of quality deterioration. g M

In any event, this has been recognized and many stabilizing agents are developed solely from the standpointv of the problem presented by the tetraethyl lead compound. Fo'r'instance, see US. Patent No. 2,560,489, dated July 10, 1951, to Smith et al. Note the following text:

It is customary in the production of high grade antiknock gasollnes to add to a good grade of gasoline, a small amount of a tetra-alkyl lead compound, usually tetraethyl lead, to reduce the tendency to cause knocking in high compression gasoline engines. The tetraethyl lead is added to the gasoline in a quantity sutficient to produce the desired anti-knock rating. In some cases a relatively small amount may be required while in other cases, for example, in the preparation of certain aviation grades of gasoline, a relatively large amount may be added. Gasoline to which a large amount of tetraethyl lead or other tetra-alkyl lead has been added is often referredto as a heavily leaded gasoline.

Although tetra-alkyl lead compounds and in particular tetraethyl lead, are eflicient for impartinganti-knock properties to gasoline, their employment is not entirely free from disadvantage. For one thing, leaded gasoline tends to develop ahazy appearance upon standing, particularly in the presence of strong sunlight. For example, in direct sunlight in the summertime, leaded gasoline may develop a perceptible liaziness after an hour or two of exposure, and longer periods of exposure result in a very marked haziness and precipitation. The formation of haze in gasoline is objectionable because the gasoline is not as marketable as a clear product; customers prefer a product which is crystal clear. A further and more important objection is that a reduction in the octane rating of the gasoline is frequently associated with haze formation; furthermore, damage is likely to occur in the fuel lines and carburetor.

"In addition to haze formation in leaded gasolines, there is a tendency to deposit gummy orresinous materials on standing, this tendency being particularly noticeable under the influence of air and light. Gum formation. as with haze formation, is usually attended by a lowering in anti-knock rating and development of a yellow or brownish color. Gum formation is also observed in engines burning the leaded gasoline, with the result that ring and valve sticking occur.

This invention has as an object the stabilization of leaded gasolines, especially heavily leaded gasolines, against haze formation.

It is a further object of this invention to protect leaded gasoline against the deposition of gum and resinous matter.

A still further object of this invention is the prevention of lowering of anti-knock rating in leaded gasolines.

In recent years, there has been a tendency to produce stabilizers whi h would stabilize a gasoline without attempting to differentiate whether the source of the difficulty is the unsaturates or the tetraethyl lead compound, or for that matter both. Note for example US. Patent No. 2,635,042. dated April 14, 1943, to Hill, which states:

It is therefore an object of my invention to provide means for protecting such hydrocarbon fuels which deteriorate in or are affected adversely by oxygen. It is a further obiect of my invention to provide a class of substances which prevents the formation of gummy oxidation and polymerization products of unstable hydrocarbons ,on contact w th oxygen. Another object of my invention is to provide means for stabilizing hydrocarbon fuels for internal combustion spark and compression ignition engines during the manufacturing, handling and storage of such fuels prior to their use. A still further object of my invention is to provide a finished gasoline, containing tetraethyl lead which will retain, during blending, storage and use, the performance characteristics inherent in the fresh fuel mixture. Still further objects of my invention will appear from the description of my invent on as hereinafter disclosed.

Many of the stabilizers employed in connection with fuels as above described are comparatively expensive organic chemicals costing from $1.00 per lb. upward. For this reason, there has been a tendency to develop less expensive compounds which act as synergists and thus reduce the cost of stabilizing a fuel. The synergist may be comparatively ineffective as a stabilizer when used alone and frequently is. but when mixed with the selected stabilizer, the combination of the two is eifective at a lower cost than the use of a stabilizer alone. Stated an other way, if one defines a synergist in conventional language as a product which in admixture produces a combination in which the sum total is greater than the effect of the individual compounds, then such terminology is suitable for the present purpose. The use of such synergist mixture is illustrated by a number of patents. See, for example, claim 1 of US. Patent No. 2,657,983, dated November 3, 1953, to Hill et al., which states:

synergistic antioxidant composition effective in inhibiting oxidation in oxygen-sensitive organic materials consisting essentially of a hydroxy arylamine antioxidant and an ester of thioglycolic acid.

The present invention is concerned with a synergistic antioxidant composition effective in inhibiting oxidation in oxldation-susceptible materials consisting essentially of a phenylene diamine, amino phenol, or a hindered alkyl phenol type of anti-oxidant, and an oxybutylated poly- '4 alkyleneamine having not over 3 nitrogen atoms in which the nitrogen atoms are separated by a radical having not over 3 carbon atoms. The synergist, for example oxybutylated ethylenediamine, will be described in greater detail later.

For purpose of convenience, what is said hereinafter is divided into six parts.

Part 1 is concerned with conventional antioxidants; the kind available on the open market and which, generally speaking, sell in the neighborhood of one dollar per pound and upward.

Part 2 is concerned with the oxybutylated polyamine of the kind previously described, which serves as a synergist. These products in many cases cost only one-third as much as the anti-oxidant with which it is used.

Part 3 'is concerned with suitable mixtures of the two components described in Parts 1 and 2 preceding in proportions which are suitable for additive purposes.

Part 4 is concerned with typical mixtures of motor gasoline or the like involving the use of a synergistic mixture described in Part 3 preceding.

Part 5 is concerned with tabular data showing the effect of a synergistic mixture in comparison with the antioxidant and absence of such synergist in regard to both cracked gasolines and leaded aviation fuels. Other data is included in order to emphasize thesignificance of the present invention and the economics and benefits to be obtained by its use.

Part 6 is concerned with the use of the synergistic mixtures herein described in connection with oxidation susceptible products other than fuels as, for example, edible products including oils, edible fats, and the like.

PART 1 The types of chemical compounds used for the stabili zation of olefinic distillates or leaded olefinic distillates,

particularly from the standpoint of deterioration as exemplified by gum formation, are well known. Note, for example, claim 1 of US. Patent No. 2.295,773, dated September 15, 1942, to Chenicek, as follows:

(1) In the stabilization of olefinic distillates against gum formation by the addition of gum inhibitors thereto. the method of increasing the etfectiveness of the gum inhibitor which comprises incorporating into the distillate, in addition to the inhibitor, an amomnium salt of an organic carboxylic acid.

Thus, more specifically, reference is made to a subsequent patent, to wit, US. 2,633,415 dated March 31, 1953, to Chenicek, and with particular reference to the following language:

Particularly satisfactory oxidation inhibitors for use in the stabilization of organic compounds and more particularly motor fuel comprise aromatic aminocomponnds. Of this group the p-aminophenols and p-phenylene diamines are being used commercially on a large scale. The preferred p-aminophenol inhibitor comprises N-nbutyl-p-aminophenol, while other satisfactory inhibitors include N-isopropyl-p-aminophenol, N-sec-butyl-o-aminophenol, N-amyl-p-aminophenol. etc. During the manufacture of N-n-butyl-p-aminophenol a minor proportion of N-N'-di-n-butyl-p-phenylene diamine is formed and the present invention is intended to include such mixtures.

Of the p-phenylene diamines, N-N-di-sec-butyl-pphenylene diamine-is being used commercially on a large scale, although it is understood that other satisfactory but not necessarily equivalent oxidation inhibitors include those in whichthe alkyl radicals attached to one or both of the nitrogen atoms comprise methyl, ethyl, propvl, butyl, tertiary butyl, amyl, etc., and that these radicals may be the same or different.

Another class of known oxidation inhibitors include the alkylphenols and particularly the trialkylphenols such as 2,4-dimethyl-6-butylphenol, etc. Still other known inhibitors include the alkoxyphenols such as Z-tertiarybuty1-4-methoxywphenol, etc. It is understood that the novel features of the present invention may be applied to any suitable oxidation inhibitor. It is understood that the inhibitor for use with food products must be non-toxic. v

Regardless of the particular oxidation inhibitor em: ployed, it has been found that the addition of a quaternary ammonium oxide serves to increase the effectiveness of the inhibitor beyond that which would normally be expected. Thus, the improved'potency exceeds that calculated from the accumulated effects of the known oxidation inhibitor and of the quaternary ammonium oxide, Thisunexpected improvement is referred to as a synergistic effect.

The four classes of anti-oxidants which I prefer are the following:

(1) Amino phenol derivatives; typical examples of this class are para-N-secondarybutylaminophenol, para- N-isopropylaminophenol and para-aminophenol itself;

(2) Phenylene diamine derivatives; typical examples of this class are N,N-ditertiarybutylphenylene diamine, N,N.'-dibutylphenylenediamine, and N,N-di-secondary 'butyl para-phenylenediamine;

(3) Kindred alkylphenol derivatives, such as 2,4-dimethyl-6-tri-methylphenol.

(4) Still other known inhibitors include the alkoxy phenols, such as Z-tertiary butyl-4-methoxyphenol.

It is to be noted that these conventional anti-oxidants are effective in either the stabilization of non-edible products such as hydrocarbon fuels and also in the case of edible products such as lard, salad oils, and the like. Needless to say, when used in edible products the selection is limited to those which are nontoxic and have been approved.

PART 2 As previously noted, Part 2 is concerned with the oxybutylated 'alkylene polyamines employed in the synergistic mixture. For practical purposes the suitable polyamines are limited to the following six types:

(1) Ethylenediamine There are other polyamines which can be used in which the same radical does not necessarily connect the nitrogen atoms of a trimer as, for example, a trimer obtained by reacting ethylene diamine with propyl imine or reacting trimethyl diarnine with ethylene imine.

Theoxyalkylations ofpolyamines has'been extensively described in the literature and since the products are basic one can frequently oxybutylate at the early stages without the addition of a catalyst. However, if desired, the catalyst may be added at the very beginning. "Generally speaking, oxybutylation takes place within'a temperature range of 105 C. to 145 C., a pressure of '0 to 45 lbs. and a time period of 2 to 6 hours. Typical examples of the oxybutylation of polyamines ofthe kind described are illustrated by the following examples:

Example 1a into the reaction mass.

30 lb. of ethylene diamine was charged into the vessel, and the temperature brought up to 125 C. 180 lbs. of butylene oxide was then run over a three-hour period. Cooling water wasapplied so as to maintain the temperature between 125-130 C. The pressure was held at 15 p.s.i.g. On cooling, the final product was found'to be a fairly viscous, brownish amber liquid. 3

Example 20:

As in Example 14, 20 lb. of ethylene diamine was charged and brought up to 125 C. To this amine had been added 0.2 lb. sodium methylate catalyst. 1 92 lb. of butylene oxide was then added over afive-hour period.

7 The final product was a clear, amber liquid, having "a moderate viscosity..

' Example 3 1 As in Example 1a, 34 lb. diethylene triamine and 0.1 lb. sodium methylate was charged into the reaction vessel. 168 lb. butylene oxide was added over a five-hour period. During the addition, temperature was maintained at 130 0, pressure at 15 p.s.i.g. The final product was similar inappearance to the product of Example 2a, preceding.

Example 4a As in Example 1a, 66 1b. of dipropylene triamine was charged into the vessel with 0.05 lb. sodium methylate catalyst. Pressure and temperature were held as in Example 3a While 180. lb. butylene oxide was added over a 2-hour period. The product was a medium viscous light brownliquid. 7

Example 5a As in Example 1a, 44 lb. of 3,37-iminobispropylamine was charged into the vessel together with 0.1 lb. sodium methylate catalyst. over a 4-hour period at a temperature of 125-130 C. and a pressure of 15-20 p.s.i.g. The final product was similar to that of Example 4a, preceding.

The amount of oxide added varies from a ratio of one mole for each amino hydrogen to as much as two moles for each amino hydrogen, and in some instances it is preferable to use an amount which is 25% in excess of the 2 moles of oxide per amino hydrogen atom. 7 Thus, with ethylene'diamine 4 or 5 moles of butylene oxide may be considered the lower limit and 8 to 10 moles of butylene oxide as the upper limit. f

In the case of triamine, such as 3,3'-iminobispropylamine 5 or 6 moles may be considered the lower limit and 10, 12 or 15 moles the upper limit. The selection of butylene oxide asthe oxyalkylating agent is based in part on its property of insolubilizing diamines or triamines. The reference to insolubilization 168 lb. butylene oxide was added are hindered phenols.

is concerned withinsolubilization in water and not insolubilization in a hydrocarbon. As is well known,

of one mole of water to four moles of butylene oxide or thereabouts, one obtains. a glycol'which-is relatively 'water insoluble; for instance, tetrabutylene glycol or, I pentabutylene glycol;

Similarly, when four or more moles'of butylene oxide are reacted with the aromas herein specified, 'a product is obtained whichin the, I mixtures indicated in Part 2 gives a combination which an aqueous wash which would tend to remove the additive or, in some/instances,- might tend to cause a haze due properties. Indeed, this property is emphasized in hereto attached claims.

' I The butyleneoxide herein employed'consists essentially of the straightchainisomers and not the iso or branched chain isomers. l Actually, with reference to thestraight chain isomer, the product used was onewhich was roughly 85% or 1 more of the 1,2-isomer and approximately of the 2,3-cisand the ,2,,3-trans-isomer with substantially none or not over, 1% of the isobutylene oxide. This is the butylene oxide commercially available in the open market.

PART 3 d Furthermore, it is important that the. synergist is soluble in and can be added directly'to the 7 fuel, such as gasoline. I

when water is treated with butylene oxide in the ratio 7 ,15 to the fact that the additive had distinct hydrophilic Part-3 .is concerned with suitable mixtures of the conventional anti-oxidants describedin Part I I and the rapidly to give a suitably liquid mixture. In the ordinary senseno reaction takes place although some antioxidants are phenols and one ,rnayhypoth'esize that a phenol salt I formed 'exceptfor the fact that generally the phenols 7 Suitable. mixtures are illustrated by the following: t Exa mple 1b A proprietary anti-oxidant containing equal weights of methyl alcohol and p-N-normal butyl amino phenol was mixed with the reaction product of Example Id. The mixing was done substantially at room temperature by adding the synergist to the anti-oxidant with mild agitation. Several blends were thus obtained, containing the following components:

Percent Percent 25 Percent 40 butyl amino phenol sol t synergist 1a;

Similar blends were made using the synergist previously described as Example 3a.

Percent Percent 40 Percent Butyl amino phenol 33. solvent. synerglst 3a t.

Example 2b Percent Percent Percent dibutyl phenylene dis-mine 50 40 v ,25 toluene 0 40 '50 synergist 1a; 50 20 25 (10c) (11c) (12c) Percent Percent Percent dibutyl phcnyleno diarntne 50 35 1 t 25 toluene 0 50 synergist 4n 50 25' 7 Example 3b Blends of synergist and the anti-oxidant ;2,4,di-tbutylp-cresol were made. This anti oxidant is normally a crystalline solid, and it is therefore preferable to employ a solvent in using it'ormixing it, such as toluene or gasoline, I I I Pcrc'ent- Percent Percent dihutyl-p-creso1. 25 35. 20, toluene 5O 30 I synergist 1a-- 25 I 35 40 Percent Percent Percent dibutyLp-crcsol 25 35 t 40 toluenetwnu- 3O 40 synerglst 2a I 25 :35 I 20 (19c) (20c) (21c) V i Percent Percent Percent dlbuty1+peresol-...- r. ,25 30 g .35 y toluene 50 y p 30 25 synergistic 25 10 40 Note,'however, that one can add the two selected cornponents to fuel, such as gasoline, in selected predetermined ratios so that mixture takes place in situ.

PART 4 Part 4 is concerned with typical mixtures of. motor gasolines or the like involving the synergistic mixtures described in Part 3, preceding.

Generally, it is important to add the anti-oxidant or synergistic mixture to the gasoline or otherhydrocarbon as soon as possible after the refining procedure. N This is generally done before the gasoline is contacted by the atmosphere, as happens in storage. One typical refinery procedure is to dilute the anti-oxidant'or synergistic mixture with the gasoline or hydrocarbon stream to be treated. This dilute solution is then metere'd from a special holding tank directlyinto the hydrocarbon stream in a continuous fashion as the hydrocarbon passes to storage.

In the case of leaded aviation gasolines, the tetraethyl lead and anti-oxidant or synergistic mixture may be metered into the hydrocarbon stream simultaneously or separately. Once again, it is usually considered important to add the inhibitor as soon as possible after addition of the tetraethyl lead.

Typical mixtures 01' blends of inhibitors and lead components are as follows:

Catalytically cracked gasoline:

5 ppm. butyl aminophenol 5 ppm. synergist 1a 10 p.p.m. butyl aminophenol -a -e r 2a 4) i 30 p.p.m. dibutyl phenylenediamine 15 p.p.m. synergist 3a 30 p.p.m. dibutyl phenylene diamine 20 p.p.m. synergist 1a 20 p.p.m. dibutyl phenyle ne diamine 30 p.p.m. synergist 4a 40 p.p.m. dibutyl p-cresol 20 p.p.m. synergist 1a 20 p.p.m. dibutyl p-cresol 20 p.p.m. synergist a Leaded gasoline;

1000 p.pm. TEL (tetraethyl lead) p.p.m. dibutyl p-cresol 15 p.p.m. synergist 1a d) 2500 p.p.m. TEL

p.p.m. dibutyl p-cresol 10 p.p.m. synergist 3a 2500 p.p.m. TEL 20 p.p.m. dibutyl p-cresol 20 p.p.m. synergist 4a 2000 p.p.m. TEL 10 p.p.m. dibutyl p-phenylene diamine 10 p.p.m. synergist 1a 1000 p.p.m.,TEL 15 ppm. dibutyl p-phenylene diamine 15 p.p.m. synergist 5a ample. 1e.

Example 1 e Two separate metering pumps, wereset. up to feed reagent into a gasoline pipe line. The pipe line was one which ran from a final refinery process to field tank storage. The one metering pump dispensedan intermediate blend of gasoline-tetraethyl lead; the other Janintermediate blend of gasoline-synergistic anti-oxidant .mixture. As the gasoline flowed toYstorageyboth metering pumps delivered their respective blend into the stream at points close by, such that by the time the gasoline reached storage, complete mixinghad occurredvia pipe line turbulence. Thus, the gasoline at the storagepoint contained in this case a combination of additives asdescribed'in Example 8d, preceding.

PARTS As previously noted, Part 5 is concerned with tabular data which illustrates the effectiveness of the synergistic mixture in comparison with the anti-oxidant alone. f

The following tabular data are obtained from a testing procedure well known in theart. This test is sometimes referred to as the induction period test, or oxygen bomb test. Briefly, the test is conducted by subjecting a sample of gasoline in a bomb to a temperature of C. at a pressure of 100 p.s.i.g. This pressure is the starting pressure, and may range up to 140-160 p.s.i.g. at 100 C. The pressuring gas in the bomb is pure oxygen, traces of air having been removed. A record of pressure versus time is made, and when the pressure drops more than two pounds in a 15-minute interval, the test is over. The time from start of heating to the pressure break is called the induction period.

Another test is known as the potential gum test. The gasoline is first aged in an oxygen bomb, as described above, for 16 hours. The sample is then evaporated quickly in a special heated bath, and any residue or gum remaining is weighed. The amount of gum formed is a measure oftthe stability ofv the'g'asoline, i.e., the less gum formed, the more stable the gasoline.

In using. both the above-mentioned'tests, gasoline samples containing different anti-oxidant and/0r synergistic mixtures, are compared. It is generally assumed that the induction periods are arelative indication of how stable the gasoline will be in actual storage'and use conditions.

- Tests on leaded aviation gas] I TABLE I Av. Gas 25 cc. TEL/L. IP, min. Percent V Increase 'DBPC= Dibutyl para cresol. v 1 Synergist 1a=Reactiou product of 5 moles butylene oxide and 1 mole ethylene diamiue. t

TABLE 11 Av. Gas 2.5 cc. TEL/L. IP, min. Percent Increase Raw 0 10 p.p.m. DBPC 28 2A] p.p.m. DBPO 950 660 5 DBPO+5 synergist 1a", V 200 v 460 10 DBPC-I-IO synergist 1a 1, 120 800 TABLE ni- Cumene 4.8 cc. TEL/L. IP, min. Percent Increase Raw- 0 i 15 p.p.m. DBPC t 780 360 7.5 DBPC+7.5 synergist 1a 780 I 360 TABLE IV Av. Gas 25 cc. TEL/L.16 Hr. Gum Test MgJlOO cc.

'Raw 69. 0 3O p.p.m. DBPC 0.7 15 DBPC+15 synergist 1a 0. 3

TABLE V 'Av. Gas 1.25 cc. TEL/L. IP, min.

30 p.p.m. synergist 1a 420 30 p.p.m. DBPO 1, 330 10 DBPC +20 synergist 1a 1, 035 2Q DB-PO +10synerg'ist 1a 1, 440+ TABLE VI Av. Gas 1.25 cc TEL/L. 11?, min.

30 DBPC, H20 washed 1, 800+ 15 PC +15 synergist 1a, H washed. 1, 800+ 30 .p.m. DBPC, caustic washed 3, 600+ 15 BPG +15 synergist la, caustic washe 3, 600+ Leaded aviation gasoline TABLE VII [2.5 cc. TEL/L] Anti-oxidant IP, min.

Raw 115 15 p.p.m. DBPC 705 30 ppm. DBPC 1, 200 15 ppm. Synergist 1c 200 15 p.p.m. Synergist la +15 ppm. DBPC 1,230 15 p.p.m. Synergist 211 +15 p.p.m. DBPC- 1, 230 15 p.p.m. Synergist 311 +15 p.p.m. DBPO 1, 300 15 ppm. Synergist 4a +15 p.p.m. DBPCL- 1, 210 15 p.p.m. Synergist +15 p.p.m. DBP 1, 215

1 DBPC=dibutyl-p-cresol.

Efiect of synergist on cracked gasolines TABLE VIII Induction Induction Induction Period increase Period increase Period, Min. at 30 p.p.m. at 15 Synergist at 15 p.p.m. para-butyl- 1a 1 +15 para- Gasoline para-butyl aminophenol butylamino- I amino-phenol or di-butyl-pphenol or dior di-butyl-pphenylene butyl-pphenylene diarnine, phenylenediamine percent diamine, percent I Socony Regular 225+78 104 InternationaL. 0544.5 --11 Texas. 335+22. 5 Mid-Oontinent 360-69 19. 5 Deep Rock" 540-41 11 Texas ..a 315+22 21 Ohio Coken. 425-49. 5 3. 5 Ohio Regular 470+34 57. 5

1 Synergist 1a=Rcaction product of 5 moles butylene oxide and 1 mole ethylene diamine.

1 Syncrgist 1a=Reaction product of 5 moles butylene oxide and 1 mole ethylene diann'ne.

Gulf coast cracked gasoline TABLE X Anti-oxidant IP, min

Raw 55 55 p.p.m. BAP 1 450 30 p.p.m. BAR. a-.. 515 15 p.p.m. Synergist m 110 15 p.p.n1. Synerg'lst 1a +1 p.p.n1 460 15 ppm. Synergist 2a +15 ppm. BAP... 425 15 ppm. Synergist 3a +15 p.p.m. BAP 400 15 ppm. Synergist 4a +15 p.p.m. BAP.-- 435 15 p.p.m. Synergist 5:: +15 p.p.n1. BAP 420 1 BAP=p-butyl amino phenol.

PART 6 for the stabilization of edible fats and oils. As to the use of anti-oxidants, and particularly synergistic mixtures for the stabilization of edible fats and oils, see U.S. Patent No. 2,738,281, dated March 13, 1956, to Chenicek et al. What is stated therein applies with equal force and eifect to the present invention for the reason that the antioxidants there employed are conventional anti-oxidants of the kind described previously in Part 1, preceding. For this reason attention is directed to the following statements verbatim as they appear in said aforementioned U.S. Patent No. 2,738,281:

It recently has been discovered that the addition of certain compounds to oxidation inhibitors, when used to stabilize edible fats and oils, prevents or retards rancidity development for a period of time far in excess of that obtainable when utilizing the oxidation inhibitor alone. This phenomenon has been termed synergism and compounds which function in this manner are called synergists.

The oxidation inhibitor to be utilized for the stabilization of edible fats and oils must meet severe requirements. The inhibitor must function to prevent or retard the development of rancidity in edible fats and oils. The inhibitor must be non-toxic so that it may be used safely without fear of possible poisoning. The inhibitor must not impart bad odor, color or taste to the fats and oils. The inhibitor must be readily soluble in fats and oils and further should not be removed therefrom during cooling or in deep fat frying due to its volatility or heat unstability. Another important property desired in the inhibitor is that it carry over. into the bakery products. Many bakery products, such as crackers, potato chips, popcorn, etc., are kept for considerable periods of time in factories, stores or in the homes before consumption. These bakery goods tend to become rancid during these long periods of storage. I

A number of oxidation-inhibitors meet the requirements hereinbefore set forth in varying degrees. A particularly preferred class of oxidation inhibitors comprises those having a phenolic configuration. It now has been found that these phenolic inhibitors may be considerably increased in effectiveness by utilizing a particular class of compounds in conjunction with the inhibitor. The particular class of compounds exert a synergistic effect in increasing the eficctivcness of the phenolic oxidation inhibitor.

In examining the stabilization of lard using the herein described synergistic mixture and following the same procedure as described in Example 1 of aforementioned U.S. Patent 2,783,281, the results appear in comparable tabular form in the table immediately following:

In the following table, the lard was subjected to a constant stream of air bubbles at a temperature of 180 F. Each sample was periodically checked for odor of rancidity.

TABLE XI.-STABILIZATION OF LAR D Antioxidant or Synergistic Mixture Time,

Hours 1 Control 2,6-ditertiarybutyl paracresol, p.p.m

Synerclst 1a 100 p. .m

2,6-ditertiarybutyl paracresol, 50 p.p.m. plus Synergist 1a,

50 p.p.m 20

Time at which lard had first definite odor of rancidity. Synergist: lots the reaction product of one mol ethylene diamine plus 5 moles butylene oxide.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. An anti-oxidant composition effective in inhibiting oxidation in oxygen-sensitive organic materials such as petroleum distillate hydrocarbon fuels for internal combustion engines and lard consisting essentially of a binary mixture of (A) and (B); said mixture being within the 13 ratio of 70% to 30% and 30% to 70% by weight, the (A) component being (A') a conventional anti-oxidant selected from the group consisting of lower alkyl amino phenols, lower dialkyl cresols and lower dialkyl phenylene diamines, and the p (B) component being oxybutylated alkylene polyamines; said precursory polyamines having 2 to 3 nitrogen atoms in which the nitrogen atoms are separated by a hydrocarbon radical having 2 to 3 carbon atoms and the ratio of butylene oxide to polyamine employed being within the range of not less than one mole and not over two moles of butylene oxide for each amino hydrogen atom.

2. The composition of claim 1 wherein the oxybutylated polyamine is ethylene diamine which has been oxybutylated with 4 to 6 moles of butylene oxide per mole of ethylene diamine.

3. The composition of claim 1 wherein the conventional anti-oxidant is para-butyl aminophenol.

4. The composition of claim 1 wherein the conventional anti-oxidant is dibutyl-para-phenylene diamine.

5. The composition of claim 1 wherein the conventional anti-oxidant is dibutyl-para-cresol.

6. A petroleum distillate hydrocarbon fuel for internal combustion engines comprising a petroleum hydrocarbon distillate fraction normally subject to deterioration in the presence of oxygen and as a principal anti-oxidant ingredient in an amount suflicient to inhibit the deterioration of the distillate fraction a. binary mixture consisting of (A) and (B); said mixture being within the ratio of 70% to 30% and 30% to 70% by weight, the (A) component being (A) a conventional anti-oxidant selected from the group consisting of lower alkyl amino phenols, lower dialkylcresols and lower dialkyl phenylene diamines, and the (B) component being oxybutylated alkylene polyamines; said precursory polyamines having 2 to 3 nitrogen atoms in which the nitrogen atoms are separated by a hydrocarbon radical having 2 to 3 carbon atoms and the'ratio of butylene oxide to polyamine employed being within the range of not less than one mole and not over two moles of butylene oxide for each amino hydrogen atom.

7. The fuel composition of claim 6 wherein said antioxidant is employed in the range of .0001% to .01% by weight. 1

8. The fuel composition of claim 6 wherein said antioxidant is employed in the range of .0001% to .01% by weight, and the hydrocarbon distillate contains a tetraalkyl lead anti-knock agent.

9. The fuel composition of claim 6 wherein said anti oxidant is employed in the range of .0001% to .01% by weight, the hydrocarbon distillate contains tetraethyl lead, and the oxybutylated polyamine is ethylene diamine which has been oxybutylated with 4 to 6 moles of butylene oxide per mole of ethylene diamine.

10. The fuel composition of claim 6 wherein said anti-oxidant is employed in the range of .000l% to .01% by weight, the hydrocarbon distillate contains tetraethyl lead, the oxybutylated polyamine is ethylene diamine which has been oxybutylated with 5 moles of butylene oxide per mole of ethylene diamine, and the conventional anti-oxidant is para-butyl aminophenol.

11. The fuel composition of claim 6 wherein said antioxidant is employed in the range of .0001% to .0l% by weight, the hydrocarbon distillate contains tetraethyl lead, the oxybutylated polyamine is ethylene diamine which has been oxybutylated with 5 moles of butylene oxide per mole of ethylene diamine, and the conventional antioxidant is dibutyl-para-phenylene diamine.

12. The fuel composition of claim 6 wherein said anti-oxidant is employed in the range of .0O0l% to .01% by weight, the hydrocarbon distillate contains tetraethyl lead, the oxybutylated polyamine is ethylene diamine which has been oxybutylated with 5 moles of butylene oxide per mole of ethylene diamine, and the conventional anti-oxidant is dibutyl-para-cresol.

13. The fuel composition of claim 10 in which the petroleum distillate hydrocarbon fuel is gasoline.

14. The fuel composition of claim 11 in which the petroleum distillate hydrocarbon fuel is gasoline.

15. The fuel composition of claim 12 in which the petroleum distillate hydrocarbon fuel is gasoline.

References Cited in the file of this patent UNITED STATES PATENTS 2,305,674 Chenicek Dec. 22, 1942 2,333,294 Chenicek Nov. 2, 1943 2,591,583 Moody et a1. Apr. 1, 1952 2,633,415 Chenicek Mar. 31, 1953 2,684,893 Hughes et a1. July 27, 1954 2,729,691 De Pree Ian. 3, 1956 2,759,021 Gaar et a1. Aug. 14, 1956 2,766,106 Oldenburg Oct. 9, 1956 2,793,944 Chenicek May 28, 1957 

1. AN ANTI-OXIDANT COMPOSITION EFFECTIVE IN INHIBITING OXIDATION IN OXYGEN-SENSITIVE ORGANIC MATERIALS SUCH AS PETROLEUM DISTILLATE HLYDROCARBON FUELS FOR INTERNAL COMBUSTION ENGINES AND LARD CONSISTING ESSENTIALLY OF A BINARY MIXTURE OF (A) AND (B); SAID MIXTURE BEING WITHIN THE RATIO OF 70% TO 30% AND 30% TO 70% BY WEIGHT, THE (A) COMPONENT BEING (A) AS CONVENTIONAL ANIT-OXIDANT SELECTED FROM THE GROUP CONSISTING OF LOWER ALKYL AMINO PHENOLS, LOWER DIALKYL CRESOLS AND LOWER DIALKYL PHENYLENE DIAMONES, AND THE (B) COMPONENT BEING OXYBUTYLATED ALKYLENE POLYAMINES; SAID PRECURSORY POLYAMINES HAVING 2 TO 3 NITROGEN ATOMS IN WHICH THE NITROGEN ATOMS ARE SEPARATED BY A HYDROCARBON RADICAL HAVING 2 TO 3 CARBON ATOMS AND THE RATIO OF BUTYLENE OXIDE TO POLYAMINE EMPLOYED BEING WITHIN IN THE RANGE OF NOT LESS THAN ONE MOLE AND NOT OVER TOW MOLES OF BUTYLENE OXIDE FOR EACH AMINO HYDROGEN ATOM. 